This invention relates to remotely controlled apparatus for disposition of radioactive waste material as produced, for example, in nuclear electric power generating stations.
Stringent laws, rules and regulations govern the disposition of radioactive wastes and their transportation over highways, on railroads and by other modes of transportation. In general, the material must be shielded so that radiations emanating from the material do not exceed maximum levels established by the laws and regulations. Furthermore, it is desired that in a case of an accident causing dumping of a radioactive load, there should be no fluidic materials that can penetrate the ground or mix with streams or ground water and cause radioactive contamination. It has therefore been proposed to provide a mixture of resin particles containing radioactive material, cement as a solidifying agent, and water in a container such as a steel drum, and to allow the mixture to solidify in the drum.
However, prior systems for putting radioactive materials into a drum or other container in general require that operators and maintenance personnel be exposed to radiation, even though such system may be intended to protect personnel. For example, the operators in many cases must go into areas containing radiation to open drums or close them or to insert nozzles in the drums or to handle the drums in storage. In some systems an operator may stand behind a shield wall, but must extend his arms into a radioactive zone, and expose his head to see, to connect pipes for feeding radioactive material. If spills occur, the operator must go into the radioactive zone to clean up spills. In prior operations where drums are stacked in multiple layers in decay storage areas, the operator must often go into such areas to place planks between the layers. Maintenance men must go into radioactive areas to work on equipment requiring maintenance at intervals, such as conveying equipment, motors, and switches. The total amount of radiation to which personnel can be safely exposed is limited by physiological reasons; therefore, personnel must be controlled as to their duties, and the amount of radiation to which they are exposed frequently checked to avoid their exposure to an excessive amount of radiation that can adversely affect health. Moreover, in operation of the nuclear plant, if an emergency should arise correction of which would require exposure of operators or maintenance men to radiation during a time when all available men had reached their limits of radiation tolerance, a shutdown of the plant might be necessary or other adverse consequences might result because of lack of operators or maintenance men having safe radiation tolerances.
Moreover, prior systems can on occasion spill radioactive materials on the outside of the drums or on the floor. If the spill is on the drum, it is necessary to decontaminate the drum prior to shipment. If the spill is on the floor, then a certain amount of dust can be generated as the material dries. Such dust, which is radioactive, could find its way through the plant and thus make the plant unsafe because of radioactivity. Spilled materials also can collect in floor drains and clog them. Prior systems for putting radioactive material into drums in general have loaded drums in an open space, so there was no way of containing or taking care of the problems caused by spills of radioactive material.
Some previous systems have numerous operating mechanical parts requiring periodic maintenance, such as motors and electrical switches, in radioactive areas. Maintenance of such equipment can expose personnel to considerable radiation.
Previous equipment loads drums containing radioactive material onto trucks or casks in a haphazard fashion, and thus, not loading the truck or cask to full capacity, would lose lading and could cause damage to the drums or drum enclosure.
Previous systems, because of loss of electrical power or air pressure or improper handling of the drum handling means, could topple a drum or cause irregularities in operation which could cause spillage of radioactive material.